How To Read Your 23andMe Results

Genetic testing has become very popular with bio-medical patients who typically have idiosyncratic chronic symptoms. This is where genetic testing comes into its own as it tests for idiosyncratic genes.

Many useful genetic tests are available within Australia but not readily accessible to a patient. This means 23andMe provides a viable option to “reverse engineer” genetic data, until genetic testing is more readily accessible.

A basic level of understanding of genetics is needed in order to read your 23andMe results. I recently met with Professor Sheffield, one of Australia’s leading geneticists, and he kindly gave me a lesson in genetics. Based on his explanation I hope to simplify genetics to empower you to read your 23andMe results.

So firstly lets talk genetics in plain english.

A genome is the whole of our genetic material. It consists of 20,000 individual genes, and a whole lot of other genetic material, the function of which is currently unknown. The genes only make up 1.5% of the genome.

That genome is then organised into 46 (23 pairs) of chromosomes. A chromosome is just a linear organisation of genes and other genetic material.

The sequence of these single chemicals within the chromosome are called bases or single nucleotides. It is these chemicals within these bases which determines how that cell will function.

These single chemicals are Adenine, Thymine, Cytosine, and Guanine. This is shown as A, T, C, or G on the 23andMe results.

Each gene has a pair of bases or single nucleotides. This is because one comes from each parent. For much of the genome this pair has the same chemical base but many pairs are different. These are called single nucleotide polymorphisms (or SNPs pronounced “snips”).

23andMe tests around 1/10th of our pairs to see which of the 4 bases are there in identical pairs. It does not test the whole of our genome.

So lets radically simplify genetics even more.

The mix of Adenine, Thymine, Cytosine, and Guanine chemicals in our genes is what makes us unique. This is what 23andMe reports.

So here is how you read your 23andMe results.

23andMe has a “browse raw data” function which is useful if you know which gene or SNP may be implicated. The search results then show the results as A, T, C, or G. The results include which of these is normally found in the whole population (from the A, T, C, or G options), and which of these is found in each one of the pair of that person (so there are two results – one for each pair).

So here is how you can interpret your 23andMe results.

23andMe no longer interprets results but provides an export facility. The whole results can be exported from 23andMe in a text file. That file can then be imported into an online report reader. A summary of the main report readers are as follows:

Reports are difficult to read and print
Information is highly technical and requires medical interpretation

None

These report readers work by comparing the 23andMe results to a database of all known genetic results to date. This is typically the NCBI database which is here. These results are then interpreted as follows:

English

Genetic Speak

Report Reader

Report Reader

Both SNPS are normal

No Variations

(-/-)

Green

One SNP has a variation and one is normal

Heterozygous

(+/-)

Yellow

Neither SNP is normal

Homozygous

(+/+)

Red

These results still need to be interpreted by a genetic counsellor.

Most SNPs tested in 23andMe are not associated with a disease but may be associated with some other function. The role that a SNP plays in the development of a disease typically depends on its location. Generally SNPs located close to a gene play a greater role in disease. This means that just because a SNP is abnormal does not mean it is relevant.

Also just because a SNP has a variation, that is linked to a particular disease, does not mean that the gene is being expressed by way of symptoms. It does, however, provide valuable information for preventative or restorative measures.

Further genetic testing is often available and provides even more medical information.

Once a genetic vulnerability has been identified by 23andMe, further genetic testing can often be accessed, which will more precisely define the appropriate medical treatment.

I have had about four highly significant medical breakthroughs following 23andMe test results. I have written about one of those breakthroughs here.

That is a perfect example of how 23andMe provided the raw data, a report reader identified an issue with my CYP2D6 gene, and DNA Dose provided the solution to my severe adverse drug reactions.

DNA Dose (a cheek brush or blood test that measures more than the 23andMe type abnormality in the gene) determined that my body was only clearing 20% of commonly prescribed drugs (where normally 100% was cleared). I was being poisoned.

So why do 23andMe?

In an ideal world a patient would have clear symptoms, that pointed a doctor to a clear diagnosis, have tests available to confirm that diagnosis, then receive effective medical treatment, and have it all bulk billed to the Government. But life is not that simple.

With a rare medical condition, or idiosyncratic symptoms, 23andMe may just provide valuable information, which may help you to help your doctor narrow down a diagnosis, and identify an effective treatment. Of course, if your concern is simply drug tolerance and dosage, then you do not need to do 23andMe, you can just skip to the end-game DNA Dose.

Aside from the Doctors listed in Livewello’s directory, do you know any other directories? Also, I just used their new Health Tool and the free reports it this new app were surprisingly easy to understand. Would appreciate your thoughts on it: https://livewello.com/genetics/health-reports

Thanks Elizabeth for your question. There are a lot of genetic counsellers out there none of whom I recommend. They are simply diagnosing and selling supplements based on genetic snps irrespective of a person’s health history and concerns. When I first started out I had a session with one of these so called genetic counsellors and was provided with a standard list with about 30 supplements and he even had the wrong snps (he thought the DAO snp was the DAO enzyme which it is not!)! Your best bet is to find someone to work with on your overall health who understands 23andMe and the key snps. At best 23and Me (and livewello) can provide a blueprint as to where further investigations may be warranted (e.g. MTHFR, CYP450 etc) after basic functional testing has been performed. Both Zoe and I work this way.

mtnwoman

Nice post! Do you know if their is an equivalent in the US to DNAdose?